Syringes are frequently used for administering drugs or other fluids to persons of widely-varying sizes, from small children to large adults, with correspondingly varied dosage requirements. Some syringes include indicia that are indicative of the fluid volume of the syringe, but measuring and administering proper dosage of a drug or fluid with such syringes typically requires calculations and accurate manipulation of the syringe to avoid overdosing or underdosing a patient. Administering the proper dosage for a given patient can be difficult since it can require carrying out a complex series of mathematical calculations. This process can be made more difficult by high stress and/or high workload environments, such as in emergency rooms, at accident scenes, or when dealing with critically ill patients, for example.